[The implications of looking at Sherlock's arm isn't lost on him, but his little brother's reaction makes him mildly suspicious. He places his own tablet down.]

I saw--

[A pause to collect himself, his voice rose with venom, irritated that he was being accused of seeing things. But annoyingly enough, Sherlock was right. It was gone. What else could it be but a trick of the light, a trick of his eyes, or a trick of this place?]

I'm not hallucinating, I saw it. Some kind of egg-shaped object.